Percentage calculation | Different shortcut methods to find out percentage

Percentage problems and solutions for aptitude

Percent means per hundred. Percentages are way of expressing hundredth. So ‘X ” percent means X per hundred or ” X/100 “. The concept of percentage mainly applies to ratios, and the percentage value of ratio is arrived at by multiplying by 100 the decimal values of ratio.

Percentage calculation plays very important role in the quantitative aptitude. Because some other topics in QA also depended on the percentage calculation.

Percentage formulas for different types of applications were already given the below like.

Example 5 : A’s salary is 30% lower than B’s salary, which is 20% lower than C,s salary. By how much percent is C’s salary more than A’s salary?

Here Take C’s salary 100 then B’s salary 100 x ( 100-20)% = 80

Now A’s salary 80 x (100-30)% = 80 x 70% = 56.

Now using the formula = X is what percent greater than Y ( here x = 100 and y = 56 )

[ (100-56) / 56 ] x 100 = 44 x 100 / 56 = 78.57%

So C salary 78.57% more than A’s salary.

For the above sum we can using one shortcut method

Lower means take negative sign for for 30% and 20%.

i. e -30 -20 + (30 x 20 / 100 ) = -44%

So A’s salary 44% less than C salary. If take C’ s salary 100 than A’s salary having 56.

Example 6 : The cost of manufacturing of a medicine is made up of four components A, B , C and D which have ratio of 4 : 3 : 1 : 6 respectively. If there are respective changes in the cost of +20% , -10% , -30% and +30%, then what would be the percentage change in cost.